Q123 / 160 · WBJEE 2010 · Physics

Two mirrors at an angle $\theta^{\circ}$ produce 5 images of a point. The number of images produced when $\theta$ is decreased to $\theta^{\circ}-30^{\circ}$ is

  • A
    9
  • B
    10
  • Correct answer
    C
    11
  • D
    12

Solution

Hints: No. of images $=5$ $\therefore \theta=60^{\circ}$ New angle $=\theta-30^{\circ}=30^{\circ}$. No of images $=\frac{360^{\circ}}{30^{\circ}}-1=11$

Hence, the correct answer is option: 'C'.

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